Percutaneous lead device

ABSTRACT

A percutaneous lead device including an element for preventing bacterial infection caused by implanting the lead through the skin. This element extends below and along the skin surface and includes an antibacterial fluid reservoir coated with a diffusion-controlling layer which maintains the desired fluid release rate. A surface configuration on the reservoir and lead which is highly adherent to and completely permeated by ingrowing tissue provides a particularly effective bacterial seal.

United States Patent Kitrilakis et al.

[451 Oct. 24, 1972 [54] PERCUTANEOUS LEAD DEVICE [72] Inventors: SotirisKitrilakis, Berkeley; Thomas C. Robinson, El Cerrito, both of Calif.

[73] Assignee: Tecna Corporation, Berkeley, Calif.

[22] Filed: Oct. 1, 1970 [21] Appl. No.: 77,290

[52] US. Cl. ..128/348, 128/260, 3/1 [51] Int. Cl. ..-.....A6lm 25/00[58] Field of Search ...l28/348, 349 R,'350 R, 214.4,

[56] References Cited UNITED STATES PATENTS- 3,447,161 6/1969 Weikel .Q..3/1 3,279,996 10/ 1966 Long et al ..424/l9 3,461,869

8/1969 Hargest ..128/348 X OTHER PUBLICATIONS Ersek et al Trans. Amer.Soc. Artif. Int. Orgs. 1969,

Vol. XV, 1969 (June) pp. 267- 271. McDonald et al. Trans. Amer. Soc.Artif. Int. Orgs. V01. XIV 1968 pp. 176- 180.

Primary Examiner-Dalton L. Truluck Attorney -Flehr, Hohbach, Test,Albritton & Herbert 7] ABSTRACT A percutaneous lead device including anelement for preventing bacterial infection caused by implanting the leadthrough the skin. This element extends below and along the skin surfaceand includes an antibacterial fluid reservoir coated with adiffusion-controlling layer which maintains the desired fluid releaserate. A surface configuration on the reservoir and lead which is highlyadherent to and completely permeated by ingrowing tissue provides aparticularly effective bacterial seal.

9 Claims, 2 Drawing Figures PERCUTANEOUS LEAD DEVICE BACKGROUND OF THEINVENTION This invention relates generally to method and means forpreventing bacterial infection caused by implanting a percutaneous leaddevice in the skin and for achieving good fixation to minimize bacterialpenetration and to avoid accidental removal of the lead.

Percutaneous lead devices such as tubes, shunts, cannulae, insulatedwire, and various rods or tubular devices have been implanted throughthe skin for a wide variety of reasons. For example, such devices areused temporarily or over long periods of time to provide access to thecirculated blood for blood pressure monitoring, blood sampling, theinfusion of various substances, and the like. These lead devices arealso used to connect external equipment to implanted devices, such asblood-flow probes, blood pumps, and pace makers. Two particularlywidespread uses are as blood vessel connections in hemodialysis and asabdominal cavity access tubes for peritoneal dialysis. Both dialysistechniques are important tools in the treatment of kidney failure.

Although there is a substantial need for chronic, or long-term, use ofpercutaneous lead devices of the aforementioned type, thepresently-available lead devices tend to cause infection by bacteriabeing transmitted across the skin and along the boundary between suchdevices and the surrounding skin tissue. Use of topical antibiotics atthe skin puncture or the use of systemic antibiotics have been onlymarginally successful in the control of such infections since surface orsystemic bacterial control does not prevent the eventual infection ofthe internal tissue. The only effective treatment of infections alongpresent leads has been the removal of the lead and infected tissue,necessitating the implantation of a lead in a new site. Such untreatedlocal infections will eventually result in systemic infections.

SUMMARY OFTHE INVENTION AND OBJECTS In accordance with the presentinvention, method and means are provided at a peripheral portion of apercutaneous lead device for releasing antibacterial fluid into thesurrounding tissue at a controlled rate upon implanting the lead deviceinto the skin. The release means includes a fluid reservoir, such as anabsorptive material to which the antibacterial fluid is applied carriedby a peripheral lead portion. In on embodiment, the coating materialcontains a plurality of microcavities which are compatible with bloodand living tissue and form a tenacious base for anchoring tissueingrowth which minimizes bacterial penetration along the lead surface.

It is a general object of the present invention to provide a method andmeans for preventing infection in a percutaneous lead device whenimplanted in the skin caused by bacteria being transmitted along thesurface.

It is another object of the invention to provide a method and means forthe controlled release of antibacterial fluid from the surface of apercutaneous lead device.

It is another object of the invention to provide a method and means forobtaining tissue fixation which avoids movement of the lead relative toadjacent tissue or accidental detachment or removal.

The foregoing and other objects will become apparent from the followingdescription when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an enlarged view of a portionof skin and subcutaneous tissue together with a percutaneous lead deviceaccording to the invention; and

FIG. 2 is an enlarged view of the portion of FIG. 1 showing the releasedevice of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to thedrawing, percutaneous lead line 10 in the form of a hollow tube isillustrated in an implanted positionafter penetration through skin 11and subcutaneous tissue 12. Line 10 may also be a solid rod such as aninsulated wire for monitoring purposes. Various uses for either type ofpercutaneous lead line are described hereinbefore. In one embodiment,line 10 includes an outer wall containing a plurality of microcavities13, such as formed in accordance with the method set forth in thecopending application Ser. No. 77,289, filed Oct. 1, 1970. Thesemicrocavities allow the skin and subcutaneous tissue to grow around theoutside walls and become permanently fixed or anchored to the wall bytissue ingrowth.

As further disclosed in the aforementioned application, the lead wallmaterial may be rigid or flexible, depending upon the particular use ofthe lead line. A flexible lead line has the desirable property ofreducing surface shear forces as caused by body movement or externalforces applied to the line.

An additional technique to increase surface area and reduce shearstresses as illustrated in FIG. 1 is the disposition of a subcutaneousportion of the lead line generally parallel to the skin surface. Thisadditional length provides increased fixation as well as otheradvantages discussed below.

Tissue growth in the microcavities forms a generally sealing interfacewhich effectively blocks the ingress of infection causingbacteria acrossthe skin for prolonged periods of time. However, this tissue seal is notcompleted until growth of the surrounding tissue into all interstices ofthe microcavity surface structure takes place. Even though this seal isformed in a relatively short period of time (e. g., several days), it isnecessary to prevent bacterial penetration into the tissue along thelead surface during seal formation. This protection is provided by themeans described herein.

According to the invention, microcavity-containing lead lines achievelong-term use by antiseptically preventing early bacterial infectionsbelow the skin. For this purpose, (e.g., antibacterial fluid reservoir14 is mounted onto peripheral lead portion 10a. To provide a slowrelease of the fluid so that it is available for a prolonged period oftime, a diffusion-controlling layer in the form of coating 16 is mountedor applied to lead portion over essentially the entire area of reservoir14 so that the reservoir is sealed. at its proximal and distal ends. Inone embodiment, reservoir 14 is an antibacterial fluid containing awick-like absorbant material such as porous cloth (e.g., knitted orwoven Dacron) or a fibrous mat e.g., Teflon felt). The antibacterialagent is applied to the material and released at a controlled ratethrough the diffusion-controlling layer 16 into the skin.

In one embodiment of a diffusion-controlling layer 16 shown in thedrawings, a plurality of elongated passages 17 are provided throughoutthe layer to promote the desired diffusion rate. Passages 17 may beformed in a similar manner to microcavities 13 or by physicallypuncturing or perforating the layer. Passages 17 may be supplemented bymicrocavities 18 of the same type as microcavities 13 throughout thecoating in such a manner that they are linked with passages 17 to formpaths through the coating of sufficient size and density to accomplishthe desired diffusion properties. Microcavities 18 also serve to permittissue ingrowth and adhesion to prevent bacterial penetration along thesurface of the layer. In an example of one such coating, an average ofabout 100 penetrations per cm of 0.1 mm length and 0.05 mm width arepositioned throughout the layer. A typical thickness for such a layer is0.001 to 0.020 inch.

- In another embodiment of a diffusion-controlling element (not shown),microcavity surface material may inherently possess the desireddiffusion rate without the need for passages 17, as exemplified byDacron cloth or a silicone rubber membrane layer.

The antibacterial fluid in reservoir 14 is of a type which is capable ofallowing tissue growth on the outer surface of the percutaneous leaddevice while preventing bacterial infection. Suitable fluids include thefollowing: maphenide acetate, silver nitrate, and silver sulfadiazine,and the like.

Antibiotic treatment is primarily beneficial from the time ofimplantation until tissue ingrowth occurs creating an effectivebacterial seal at the tissue-microcavity surface. Thus, the antibioticis supplied in amounts to be consumed at approximately that time.

The antibiotic treatment is maintained until complete tissue ingrowthand fixation occur, and may be discontinued at this time because aneffective bacterial seal is created at the tissue-microcavity surface.If antibiotic treatment is discontinued, then means for preventingbacterial invasion of reservoir 14 are provided. These means include animpervious coating external to the skin (coating 18) which is eitherapplied prior to implantation or at the time antibacterial treatment isstopped. If the reservoir is wholly beneath the surface of the skin,then no surface coating need be applied. In either case, the reservoircan be filled with an inert substance (curable silicon rubber, siliconegrease) to prevent bacterial growth within the reservoir.

In general, it is noted that reservoir 14 may extend to any desireddegree above the surface of the skin or therebelow. The reservoir mayextend above the skin or may terminate just below the skin in thesubcutaneous tissue as shown in FIG. 1.

After depletion of antibiotic, a pathway may be formed for bacteriathrough the porous coating 16 and empty reservoir 14 into the skin. Toprevent this, it is preferred to terminate the reservoir and coatingjust below the skin in the subcutaneous tissue so that permeable layer16 is not exposed. If it is desired to extend the reservoir above theskin, then the externally projecting portion of layer 16 should berendered impermeable as by application of an impermeable coating priorto implantation or after termination of treatment.

Depletion of antibiotic fluid may also provide a site for bacteriagrowth in body fluids which difiuse through layer 16. This may beavoided by filling the depleted reservoir with an inert substance (e.g.,curable silicone rubber or silicone grease) after antibiotic fluiddepletion.

To form the antiseptic means for preventing infection according to theinvention, the bacterial fluid is first supplied to reservoir 14 eitherbefore mounting layer 16 or thereafter as through a hypodermic needlepenetrating the coating.

We claim:

1. A percutaneous device comprising an elongated lead adapted topenetrate the skin, said lead including a portion having an externalsurface compatible with skin, subcutaneous tissue and other tissue, saidsurface including pockets extending into said surface for receivingingrowth of living cells to permanently anchor the lead, antisepticmeans including an antibacterial fluid reservoir for providing acontrolled release of said fluid adjacent said portion of the lead, saidreservoir including a walled chamber attached to said lead, said chamberwalls provided with diffusion controlling passage means so that uponpenetration of the skin by the device the fluid is released directlyfrom said reservoir into the area around said reservoir portion over aprolonged period of time to prevent bacterial penetration into thetissue along the lead during ingrowth of said cells.

2. A lead device as in claim 1 in which said reservoir comprises anantibacterial fluid-containing absorptive material carried within saidchamber of the lead.

3. A percutaneous lead as in claim 2 in which said release meansincludes a permeable barrier covering said absorptive material.

4. A percutaneous lead device as in claim 3 in which said barrier is alayer extending over essentially the entire surface of the absorptivematerial.

5. A percutaneous lead device as in claim 4 in which said layer iscovered by a material which is compatible with living tissue having aplurality of microcavities of predetermined size and shape.

6. A percutaneous lead device as in claim 4 in which said layer has athickness of from 0.001 to 0.020 inch.

7. A percutaneous lead as in claim 4 in which said layer is capable ofanchoring tissue ingrowth on its outer surface.

8. A percutaneous lead device as in claim 5 including elongated passagesthrough said layer of a size sufficient for permeability.

9. A percutaneous device comprising an elongated hollow lead adapted topenetrate the skin, said lead including a portion having a flexibleexternal surface compatible with skin, subcutaneous tissue and othertissue, said surface portion including a plurality of adjacentsubstantially discrete pockets having openings which face toward thetissue, the walls of said pocket being of such shape and size as toprovide means to accommodate a number of living cells sufficient toprovide anchoring but not so large as to prevent essentially normaltransfer of nutrients to said living cells in said pockets from saidadjacent area of tissue, antiseptic means including an antibacterialfluid reservoir for providing a controlled release of said fluidadjacent said portion of the lead, said reservoir including a walledchamber attached to said lead, said chamber walls provided withdiffusion controlling passage means so that upon penetration of the skinby the device the fluid is released directly from said reservoir intothe area around said reservoir portion over a prolonged 5 period of timeto prevent bacterial penetration into the tissue along the lead duringingrowth of said cells.

2. A lead device as in claim 1 in which said reservoir comprises anantibacterial fluid-containing absorptive material carried within saidchamber of the lead.
 3. A percutaneous lead as in claim 2 in which saidrelease means includes a permeable barrier covering said absorptivematerial.
 4. A percutaneous lead device as in claim 3 in which saidbarrier is a layer extending over essentially the entire surface of theabsorptive material.
 5. A percutaneous lead device as in claim 4 inwhich said layer is covered by a material which is compatible withliving tissue having a plurality of microcavities of predetermined sizeand shape.
 6. A percutaneous lead device as in claim 4 in which saidlayer has a thickness of from 0.001 to 0.020 inch.
 7. A percutaneouslead as in claim 4 in which said layer is capable of anchoring tissueingrowth on its outer surface.
 8. A percutaneous lead device as in claim5 including elongated passages through said layer of a size sufficientfor permeability.
 9. A percutaneous device comprising an elongatedhollow lead adapted to penetrate the skin, said lead including a portionhaving a flexible external surface compatible with skin, subcutaneoustissue and other tissue, said surface portion including a plurality ofadjacent substantially discrete pockets having openings which facetoward the tissue, the walls of said pocket being of such shape and sizeas to provide means to accommodate a number of living cells sufficientto provide anchoring but not so large as to prevent essentially normaltransfer of nutrients to said living cells in said pockets from saidadjacent area of tissue, antiseptic means including an antibacterialfluid reservoir for providing a controlled release of said fluidadjacent said portion of the lead, said reservoir including a walledchamber attached to said lead, said chamber walls provided withdiffusion controlling passage means so that upon penetration of the skinby the device the fluid is released directly from said reservoir intothe area around said reservoir portion over a prolonged period of timeto prevent bacterial penetration into the tissue along the lead duringingrowth of said cells.